title: Pheophytinization kinetics of chlorophyll c under weakly acidic conditions: effects of acrylic acid residue at the 17-position.
abstract: Pheophytinization of chlorophyll (Chl) c1, which was isolated from the diatom Chaetoceros gracilis, was kinetically analyzed under weakly acidic conditions, and was compared with that of protochlorophyllide (PChlide) a and chlorophyllide (Chlide) a. Chl c1 possessing a trans-acrylic acid residue at the 17-position exhibited slower pheophytinization kinetics than PChlide a and Chlide a, both of which possessed a propionic acid residue at the same position. The difference in pheophytinization properties between Chl c1 and (P)Chlide a was ascribable to the electronegativity of the 17-substituent in Chl c1 larger than that of (P)Chlide a due to the C17(1)-C17(2) double bond with the conjugated 17(2)-carboxy group in Chl c1. Demetalation kinetics of PChlide a was slower than that of Chlide a, which originated from the effect of the π-macrocyclic structures.
authors.affiliation: Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan.
authors.forename: Kana
authors.initials: K
authors.lastname: Sadaoka
authors.forename: Sunao
authors.initials: S
authors.lastname: Shoji
authors.forename: Keiya
authors.initials: K
authors.lastname: Hirota
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsukatani
authors.forename: Taichi
authors.initials: T
authors.lastname: Yoshitomi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tamiaki
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kashimura
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Saga
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D002734:Chlorophyll / Q000737:chemistry* / Q000378:metabolism; D002735:Chlorophyllides / Q000737:chemistry; D017377:Diatoms / Q000737:chemistry / Q000378:metabolism; D007536:Isomerism; D007700:Kinetics; D011521:Protochlorophyllide / Q000737:chemistry
chemical_list: D000179:Acrylates; D002735:Chlorophyllides; D002734:Chlorophyll; C034388:chlorophyllide a; C064041:chlorophyll c; D011521:Protochlorophyllide; C036658:acrylic acid
keywords: Chlorophyll c; Chlorophyllide; Demetalation; Photosynthesis; Protochlorophyllide